Sailing With Only One Sail Up

Balancing Your Sail Plan

Most sailboats are designed to sail pretty well in 5 to 15 knots of breeze.  The boat heels a bit and the sails push the boat along at a nice pace.  It’s when the breeze gets stronger and the boat begins to heel more than 20 degrees that things don’t seem to work out as well.

To understand why, we need to think about the way the mainsail and the head sail (jib) work together.  To do this we need some basic understanding of a couple of terms.  The first term is Center of Lateral Plane (CLP).  CLP is the balance point of the underwater shape of your hull – including the keel and rudder.  This can easily be determined by taking a side view picture of your boat and then cutting out the part of the boat that is below the waterline.  If you use construction paper or another stiff paper, you can easily find the fore/aft balance point.  CLP is usually between one-third and one-half of the way aft on your keel.

The other term is Center of Effort (CE) of the sails.  Each sail has its own CE and to figure the CE of the sail plan connect the two CE’s and divide the line roughly in half.  Of course, if you have a really small headsail, or a really large mainsail, you will need to proportionately place the “center”.

Most sailors like to have just a bit of weather helm tugging on the tiller so that it is easier to feel the boat sailing through the water.  And, if something goes “wrong” you can let go of the tiller and the boat will turn up toward the eye of the wind and coast to a stop.  To have this slight weather helm, sailboats are designed so that the CE for the sail plan is slightly aft of the CLP.  And, as long as the boat is sailed in moderate breezes, the boat will sail easily and (better yet) predictably.

However, when the wind pipes up and the boat is heeled 20 degrees over (or even farther) which is uncomfortable for guests and crew… additional factors come into play.  And, the boat often becomes unstable and rounds up into the eye of the wind quickly and (often) violently.  Sometimes the jib gets back-winded and pushes the bow over and into an inadvertent tack… often followed by the boat continuing to turn quickly and an uncontrolled jibe.  If you have not experienced this yet – trust me, it is scary and dangerous.

  It is obvious that there is too much sail area up and that we need to reduce that sail area.  Some skippers opt for dousing the jib sail either by dropping the sail if the jib is hanked on or furling the jib if there is a roller furler.  But, this action probably won’t have the desired effect.

The reason that the desired effect doesn’t happen is that the mainsail is still fully hoisted.  So, the wind still has a lot of leverage to tip (heel) the boat.  The boat still heels farther than you really want.  But, even worse, with only the mainsail up the CE is much farther aft of the CLP.  The sail plan acts like a giant wind vane and the mainsail tries to spin the boat so that the bow points at the wind.  It is often very difficult to steer, the passengers are becoming nervous, and no one is having any fun.  And, you may find yourself in one of those uncontrolled tack/jibe situations again.  Solution, take the mainsail down and start the motor.

Of course, dousing the mainsail means that the boat is at the mercy of the waves and the boat’s motion through the water is rough.  The boat pounds and cork-screws around.  Everyone is hanging on for dear life.  The chances of you crew coming back for another sail becomes increasingly less as the time back to the marina goes on.

So, another option is to douse the mainsail and just use the jib sail.

Not only is this often worse, it is often a lot worse.  The chances are that the CE is not much lower than before.  So, the boat is still healing over.  And with only the jib up, the CE has moved a lot forward from the CLP.  The wind vane effect now tries to turn the bow away from the wind – making it impossible to steer a course to windward.  Plus, there is the real danger of unexpected jibes as the boat hurtles downwind.

The problem is that taking down only one sail destroys the designed balance of the sail plan and moves the CE unexpectedly too far away from the CLP.

A better solution than dousing either sail is to tuck in a reef in the mainsail.

When you reef the mainsail, the CE is lowered significantly.  So, heeling over is reduced to much more comfortable angle.  And, the overall CE of the sail plan does not change much – so, the boat stays in balance and steering improves because the boat is sailing flatter.  Many sailors say that tucking in a reef gives the boat a feel almost like having power steering.  Many racers say that “flat is fast”.  The sail plan balances; the boat heels less, so the sails are working closer to 100% effort.  The boat becomes much easier to steer on any course.  And, the boat probably even picks up some speed.

You still might decide that you need to reduce the size of the jib sail…  but, even with a smaller jib sail, the boat will be nominally in balanced with the reefed main up.

Snickerdoodle is a tall-rig Catalina 25.  All of her sails are significantly larger than a “standard-rig”.  So, I have set up the boat with three different reefing points (each taking more or less area away from the mainsail; and at the same time lowering the CE).  I also have multiple jib sails – from very large ones, down to a storm jib.  By using various combinations of reefs and jibs, I can keep Snickerdoodle in balance, relatively flat, and fun to sail.

Here is an idea as to wind vs. sails that I use:

Wind Speed           Sail Choice

2 – 7 knots            Full main sail and 150% drifter jib

8 – 11 knots           Full main sail and 150% Genoa jib

11 – 16 knots          Flattening reef in main and/or 135% Genoa jib

16 to 20 knots       First full reef and 135% Genoa jib

21 – 24 knots         First full reef and either 110% working jib or 95% blade jib

25 – 30 knots        Second full reef and 110% working jib (Gale force wind starts)

31 – 35 knots         Second full reef and storm jib

Above 35 knots, I get off the water and into the closest marina or sheltered bay as quickly as I can.  It is just not much fun to be sailing in gale force winds… let alone higher winds.

A word to the wise - -

If (right now) your boat doesn’t have reef points on the mainsail, seek out a sailmaker and have at least one full set of reef points sewn into the sail.

When that is accomplished and before you bend on the mainsail - -  Install all of the necessary gear (jiffy reefing hardware and lines) that will help you quickly and easily reef the mainsail… and have this gear permanently rigged so that it will be ready for use any time you are out sailing.

Determine what your plan is for handling situations when the boat develops extreme heel or strong weather helm.  Practice your plan on days when you have moderate breezes so that you will be ready when the wind pipes up or the storm breaks on you.  Yes, you can just douse one or the other of the sails.  But, your boat will then be out of balance and you will be fighting the weather vane created by only one sail.

Barnacle Bill Holcomb      

barnaclebillholcomb@gmail.com

509 993 3214